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occasionally some nucleotides are inserted or deleted in a sequence.
This is rare, rarer than reassortment, so we can track the evolution
since such an insertion or deletion without being distorted
by another deletion/insertion.
The lengths of the insertions/deletions are usually divisible by 3
and involve whole amino-acids.
What examples do we have ?
1) the HA-cleavage site with many examples.
In H5 and H7 this gives LP-->HP changes, rarely(if ever ?)
back from HP-->LP
2) the 60 nucleotides-deletion in H5N1 segment 6,NA
3) the 15 nucleotide-deletion in H5N1 segment 7,MP
4) the 3 nucleotide-deletion in H1N1 segment 4,HA
5) 3 nucleotide-deletion in H5N1 , segment 4,HA (I think-mentioned by niman
)
...
others ?
now, I wonder about the mechanism of these insertions/deletions,
do they just happen once or is there some predetermination
in several genetical backgrounds ?
This is rare, rarer than reassortment, so we can track the evolution
since such an insertion or deletion without being distorted
by another deletion/insertion.
The lengths of the insertions/deletions are usually divisible by 3
and involve whole amino-acids.
What examples do we have ?
1) the HA-cleavage site with many examples.
In H5 and H7 this gives LP-->HP changes, rarely(if ever ?)
back from HP-->LP
2) the 60 nucleotides-deletion in H5N1 segment 6,NA
3) the 15 nucleotide-deletion in H5N1 segment 7,MP
4) the 3 nucleotide-deletion in H1N1 segment 4,HA
5) 3 nucleotide-deletion in H5N1 , segment 4,HA (I think-mentioned by niman
)
...
others ?
now, I wonder about the mechanism of these insertions/deletions,
do they just happen once or is there some predetermination
in several genetical backgrounds ?